#define DEV_SIZE SZ_2G
 #define EFFECT(x) (1U << x)
 
+#define MOCK_INJECT_DEV_MAX 8
+#define MOCK_INJECT_TEST_MAX 128
+
 static struct cxl_cel_entry mock_cel[] = {
        {
                .opcode = cpu_to_le16(CXL_MBOX_OP_GET_SUPPORTED_LOGS),
                .opcode = cpu_to_le16(CXL_MBOX_OP_GET_POISON),
                .effect = cpu_to_le16(0),
        },
+       {
+               .opcode = cpu_to_le16(CXL_MBOX_OP_INJECT_POISON),
+               .effect = cpu_to_le16(0),
+       },
 };
 
 /* See CXL 2.0 Table 181 Get Health Info Output Payload */
                        cpu_to_le64(SZ_256M / CXL_CAPACITY_MULTIPLIER),
                .total_capacity =
                        cpu_to_le64(DEV_SIZE / CXL_CAPACITY_MULTIPLIER),
+               .inject_poison_limit = cpu_to_le16(MOCK_INJECT_DEV_MAX),
        };
 
        put_unaligned_le24(CXL_POISON_LIST_MAX, id.poison_list_max_mer);
        return 0;
 }
 
+static struct mock_poison {
+       struct cxl_dev_state *cxlds;
+       u64 dpa;
+} mock_poison_list[MOCK_INJECT_TEST_MAX];
+
 static int mock_get_poison(struct cxl_dev_state *cxlds,
                           struct cxl_mbox_cmd *cmd)
 {
        return 0;
 }
 
+static bool mock_poison_dev_max_injected(struct cxl_dev_state *cxlds)
+{
+       int count = 0;
+
+       for (int i = 0; i < MOCK_INJECT_TEST_MAX; i++) {
+               if (mock_poison_list[i].cxlds == cxlds)
+                       count++;
+       }
+       return (count >= MOCK_INJECT_DEV_MAX);
+}
+
+static bool mock_poison_add(struct cxl_dev_state *cxlds, u64 dpa)
+{
+       if (mock_poison_dev_max_injected(cxlds)) {
+               dev_dbg(cxlds->dev,
+                       "Device poison injection limit has been reached: %d\n",
+                       MOCK_INJECT_DEV_MAX);
+               return false;
+       }
+
+       for (int i = 0; i < MOCK_INJECT_TEST_MAX; i++) {
+               if (!mock_poison_list[i].cxlds) {
+                       mock_poison_list[i].cxlds = cxlds;
+                       mock_poison_list[i].dpa = dpa;
+                       return true;
+               }
+       }
+       dev_dbg(cxlds->dev,
+               "Mock test poison injection limit has been reached: %d\n",
+               MOCK_INJECT_TEST_MAX);
+
+       return false;
+}
+
+static bool mock_poison_found(struct cxl_dev_state *cxlds, u64 dpa)
+{
+       for (int i = 0; i < MOCK_INJECT_TEST_MAX; i++) {
+               if (mock_poison_list[i].cxlds == cxlds &&
+                   mock_poison_list[i].dpa == dpa)
+                       return true;
+       }
+       return false;
+}
+
+static int mock_inject_poison(struct cxl_dev_state *cxlds,
+                             struct cxl_mbox_cmd *cmd)
+{
+       struct cxl_mbox_inject_poison *pi = cmd->payload_in;
+       u64 dpa = le64_to_cpu(pi->address);
+
+       if (mock_poison_found(cxlds, dpa)) {
+               /* Not an error to inject poison if already poisoned */
+               dev_dbg(cxlds->dev, "DPA: 0x%llx already poisoned\n", dpa);
+               return 0;
+       }
+       if (!mock_poison_add(cxlds, dpa))
+               return -ENXIO;
+
+       return 0;
+}
+
 static int cxl_mock_mbox_send(struct cxl_dev_state *cxlds, struct cxl_mbox_cmd *cmd)
 {
        struct device *dev = cxlds->dev;
        case CXL_MBOX_OP_GET_POISON:
                rc = mock_get_poison(cxlds, cmd);
                break;
+       case CXL_MBOX_OP_INJECT_POISON:
+               rc = mock_inject_poison(cxlds, cmd);
+               break;
        default:
                break;
        }